Northern Renaissance artists used a combination of multiple perspectives to compose their works. These included linear, atmospheric, and intuitive perspective. 
Linear perspective includes one vanishing point and all things in the painting can be traced with a straight line back to that vanishing point. 
Atmospheric perspective refers to the change in color and clarity of objects in the distance to convey how humans see things from far away in real life. 
Intuitive perspective can't be traced back to a single vanishing point like linear perspective, but objects are placed in specific color, clarity, or position relative to the other objects in order to convey depth.
These modes together created a highly detailed and deep painting that allowed the viewer to understand which items were closer to the front or further away. Figures in Northern Renaissance painting dominated the space, with the background built around their presence and atmosphere. This arrangement led to the widely popular "triangle composition" where figures in the painting would be placed in a triangle formation, with the central figure also being taller than the rest. 
The triangle shape also carried into triptych paintings. Triptychs were three-paneled paintings backed and lined with wood that often displayed multiple religious scenes. These were used for private worship in churches or hung in people's homes to showcase their devotion to God. 
Triptychs were viewed from left to right. Triptychs also gave the artist the opportunity to work with more space and put more symbolic images into their work.